The tensile ductility of the Ni3Al（Zr） alloy is sensitive to temperature and exists low ductility from 700 to 1050℃ both in air and 10^-3 Pa vacuum. The fracture mode becomes intergrangular. The formation of oxide layer during tensile process at elevated temperature in air suppresses environmental embrittlement for the alloy. It is found that Al-rich oxide film is more effective in protecting the underlying alloy from oxygen penetration. Zr element presented in appropriate quantity can increase the ductility at intermediate temperature by their interaction with diffusing oxygen atoms.